So I started my car today for the first time in a couple of weeks. It barely started, but when it did there was a tapping sound coming from the engine bay. The sound only happened when the car was under 1500 RPMs. As the car warmed up the sound got quieter and eventually went away. Any idea what this could be?

Its a '98 LS1 btw.

 

I'd imagine that the lifters bled down. My 02 LS1 is noisier than normal when it sits for a couple of weeks or more.

 

Have you heard of Piston Slap?

 

Check out http://www.pistonslap.com

My buddy just traded in his nearly new 2002 extended cab, 4WD with 5.3 because it recently generated a bad case of piston slap.

There are some good sound clip samples on the site to listen to.

 

Well I would say its definitely piston slap. I haven't had any problems with this before but all of a sudden it started. Any known remedies to this problem?

 

If you have headers on this vehicle make sure that its not them before you go crazy about it. My 99 c5 started to make a whooshing, ticking sound after my long tubes were installed.

 

Sounds typically like piston slap been a big prob in in Aust with the LS1 Holden has had to rebuild over 2000 engines...

 

more than likely its not piston slap (IMO) b/c it does it when the engine is cold. That is 90% of the time a sign of a bad lifter.

Josh S.